JPH10316616A - Production of gamma-resorcylc acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound useful as a synthetic intermediate for agrochemicals in high yield by hydrolyzing a relatively readily available dichlorobenzoic acid in the presence of a specific catalyst. SOLUTION: The hydrolytic reaction of 2,6-dichlorobenzoic acid is carried out in the presence of a copper compound (preferably cuprous chloride, cupric chloride, cuprous oxide, cupric oxide or cupric sulfate, etc.) and secondary amines selected from dimethylamine or amine compounds represented by the formula (Z is an atomic group required to form a 5- to an 8-membered nitrogen- containing heterocyclic ring) (preferably morpholine, piperidine, pyrrolidine or piperazine) in the presence of water in at least a stoichiometric amount, preferably in a molar amount of 25 times based on the 2,6-dichlorobenzoic acid usually at 50-150 deg.C, preferably 90-110 deg.C usually for 6-36 hr, preferably 8-24 hr to afford the objective compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel method for producing γ-resorcinic acid, which is useful as a synthetic intermediate for pesticides.

[0002]

2. Description of the Related Art As a method for producing .gamma.-resorcinic acid (resorcin-2-carboxylic acid or 2,6-dihydroxybenzoic acid), a method based on the Kolbe-Schmitt reaction of resorcinol has been proposed in JP-A-5-194313. I have. Also, J. Am. Chem. Soc., 62, 667 (1940) describes a method of lithifying resorcin and then carbonating it. However, these methods produce not only γ-resorsinic acid but also a considerable amount of β-resorsinic acid, and it has been difficult to obtain highly pure γ-resorsinic acid with good selectivity. Also, J. Chem. Soc., 3499 (1952) describes a method for producing γ-resorcinic acid in which 2,6-dimethoxybenzoic acid is demethylated with aluminum chloride. Is usually difficult to obtain, and the solubility of the intermediate salt is low, so that there is a problem in industrial implementation. As a technique related to these, a hydrolysis reaction of benzoic acid substituted with a halogen atom is described in Japanese Patent Application Laid-Open No. 6-293700.
There has been proposed a method of obtaining 6-chlorosalicylic acid by hydrolyzing 6-fluorobenzoic acid at a high temperature under pressure in the presence of an alkali. German Patents 1,234,230 and 1,279,684 describe a process for producing 4-chlorosalicylic acid by hydrolyzing 2,4-dichlorobenzoic acid in the presence of a copper compound catalyst and secondary amines.
In these methods, only one halogen atom is converted to a hydroxyl group. When one halogen atom is hydrolyzed and converted to an electron-donating hydroxyl group, the remaining halogen atoms decrease in reactivity. It is not hydrolyzed.

[0003]

Accordingly, the present invention provides
It is an object of the present invention to provide a method capable of producing γ-resorcinic acid in a high yield by using relatively easily available starting materials.

[0004]

Means for Solving the Problems The present inventors have made intensive studies in view of the above-mentioned problems, and as a result, have found that γ is obtained by hydrolyzing 2,6-dichlorobenzoic acid, which is relatively easily available, in the presence of a specific catalyst. -It has been found that resorcinic acid can be produced, and the present invention has been accomplished based on this finding. That is, the present invention provides (1) a method of subjecting 2,6-dichlorobenzoic acid to a hydrolysis reaction in the presence of a copper compound and dimethylamine or a secondary amine selected from amine compounds represented by the following formula (I). Characteristic method for producing γ-resorcinic acid

[0005]

Embedded image

(Wherein Z represents an atom group necessary for forming a 5- to 8-membered nitrogen-containing heterocyclic ring). (2) The secondary amine represented by the above formula (I) is morpholine , Piperidine, pyrrolidine or piperazine, the method for producing γ-resorcinic acid according to (1), and (3) the copper compound is cuprous chloride, cupric chloride, cuprous oxide, cupric oxide or sulfuric acid An object of the present invention is to provide a method for producing γ-resorcinic acid according to (1) or (2), which is at least one selected from cupric copper.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, 2,6-dichlorobenzoic acid is converted into a compound in the presence of a copper compound and a secondary amine.
Γ-resorcinic acid can be produced preferably by hydrolysis in a solvent. The 2,6-dichlorobenzoic acid used in the present invention can be produced by a usual method. Specifically, for example, it can be produced by hydrolysis of 2,6-dichlorobenzonitrile or oxidation of 2,6-dichlorotoluene or 2,6-dichlorobenzaldehyde. As the copper compound used as the catalyst in the present invention, cuprous salts or cupric salts or cuprous oxides or cupric oxides can be used without particular limitation, and from the viewpoint of availability, Cuprous chloride,
Cupric chloride, cuprous oxide, cupric oxide, and cupric sulfate are preferably used. The amount of the copper compound to be used is preferably 1 to 20 mol% based on 2,6-dichlorobenzoic acid, and is 5 to 1 mol%.
0 mol% is more preferred. The use amount of the copper compound affects the reaction time. If the use amount is too small, the reaction time increases, and the productivity decreases. On the other hand, if the amount is too large, it becomes difficult to control the reaction, and the yield decreases.

The amines used in the catalyst of the present invention are secondary amines, and primary and tertiary amines cannot achieve the desired effects. Dimethylamine can be used as the aliphatic secondary amine, and those having a large substituted alkyl group such as diethylamine are not suitable for the method of the present invention. Further, as the nitrogen-containing heterocyclic compound, a 5- to 8-membered, preferably 5- or 6-membered heterocyclic compound represented by the above formula (I) can be used, and Z may include a nitrogen atom, an oxygen atom and the like. Good. Specifically, for example, morpholine, piperidine, pyrrolidine, piperazine, hexamethyleneimine,
Heptamethyleneimine and the like are preferable, and morpholine, piperidine, pyrrolidine or piperazine is preferable. These heterocyclic compounds may be substituted,
The carbon at the α-position of the nitrogen atom shown in formula (I) must be unsubstituted. The use amount of these secondary amines is 2,
3 to 7 times mol is preferable to 6-dichlorobenzoic acid,
The molar ratio is more preferably 4.5 to 6 times.

Although the reaction of the present invention requires at least a stoichiometric amount of water, it is preferably reacted with 2,6-dichlorobenzoic acid in the presence of 25 times or more moles of water, more preferably Water is used in a molar amount of 30 to 50 times, and an excess amount is used also as a reaction solvent. In this case, if necessary, it can be used as a mixed solvent to which an organic solvent such as alcohols is added. The reaction temperature in the present invention is usually 5
The reaction temperature is 0 to 150 ° C, preferably 90 to 110 ° C, and the higher the reaction temperature, the shorter the reaction time. The reaction pressure in the present invention is not particularly limited, and the reaction is sufficiently performed at normal pressure. However, when a secondary amine having a low boiling point is used, the pressure is increased to 1.5 to 2.5 kg / cm ^2. It is preferable to use an autoclave since the reaction proceeds more effectively. The reaction time in the present invention varies depending on various conditions such as the amount of the copper compound and the reaction temperature, but is usually from 6 to 36.
Hours, preferably 8 to 24 hours.

In the present invention, after the completion of the above reaction, γ-resorcinic acid can be separated by a usual method. That is, after recovering the secondary amines by distillation, an acid such as sulfuric acid or hydrochloric acid is added to precipitate γ-resorcinic acid, which can be extracted by filtration or extraction with an organic solvent. Further, if necessary, it can be purified by a method such as crystallization.

[0011]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Example 1 110 g (0.576 mol) of 2,6-dichlorobenzoic acid, 4.1 g (0.029 mol) of cuprous oxide, 301 g (3.456 mol) of morpholine and 518 g of water (28.
746 mol) and reacted at 100 ° C. for 14 hours.
After cooling to room temperature, the reaction solution was analyzed by liquid chromatography. As a result, 65 g of γ-resorcinic acid and a yield of 72.
It was formed at 5%. Further, 11.5 g of hydrosulfite was added to the reaction solution and reacted at 40 ° C. for 1 hour. After filtering off the insoluble matter, 72 g of a 48% aqueous sodium hydroxide solution was added, and morpholine was recovered by distillation.
145 g of 78% sulfuric acid was added, and the precipitate was taken out by filtration. When this was recrystallized from water, γ-resorcinic acid having a purity of 99% or more was obtained. After acidification with sulfuric acid, the precipitate was extracted with methyl butyl ketone, washed with water, the solvent was distilled off, and the residue was recrystallized from water to obtain γ-resorcinic acid having a purity of 99% or more.

Examples 2 to 9 2,6-dichlorobenzoic acid, amines and copper compounds shown in Table 1 and water were used at a molar ratio shown in Table 1 and reacted at a reaction temperature and a reaction time shown in Table 1. Was. After the reaction solution was cooled, it was analyzed in the same manner as in Example 1, and it was confirmed that γ-resorcinic acid was produced in the yield shown in Table 1.

[0013]

[Table 1]

Comparative Examples 1 to 16 Using 2,6-dichlorobenzoic acid, cuprous oxide as a copper compound and the amines shown in Table 2, 2,6-dichlorobenzoic acid: copper compound: amines: water 1: 0.05:
It was charged at a ratio of 6:10 (molar ratio) and reacted at 90 ° C. for the time shown in Table 2. However, in Comparative Example 1, the amount of water was 100 times the molar amount of 2,6-dichlorobenzoic acid.
After the reaction solution was cooled to room temperature and analyzed in the same manner as in Example 1, the yield of γ-resorcinic acid produced was as shown in Table 2.

[0015]

[Table 2]

From the results shown in Tables 1 and 2, γ-resorcinic acid was not formed at all or only in a very low yield in Comparative Examples, whereas in each Example, γ-resorcinic acid was not formed at all.
Γ-resorcinic acid was produced in a yield exceeding 0%. Thus, according to the method of the present invention, γ-resorcinic acid can be obtained in high yield from 2,6-dichlorobenzoic acid by reacting a copper compound with a specific secondary amine in the presence of the compound. We can see that we can do it.

Comparative Example 17 2,4-Dichlorobenzoic acid (40 g), cuprous oxide (1.5)
g and 109.5 g of morpholine were added to 188 g of water.
The reaction was performed at 0 ° C. for 10 hours. After cooling to room temperature, the reaction solution was analyzed by liquid chromatography. As a result, no production of β-resorcinic acid was observed, and the main product was 4-chlorosalicylic acid.

[0018]

According to the method of the present invention, 2,6-dichlorobenzoic acid is used as a raw material to produce an excellent action and effect that a high-yield, high-purity γ-resorcinic acid can be produced.
The 2,6-dichlorobenzoic acid and the copper compound used in the present invention are relatively easily available, and the produced γ
-The method of the present invention is suitable as a method for producing γ-resorcinic acid on an industrial scale, since separation and purification of resorcinic acid can be easily performed by a usual method.

Continued on the front page (72) Inventor Toshihiro Aiba 328 Shiotani Hamano, Fukuda-cho, Fukuda-cho, Iwata-gun, Shizuoka K-I Kasei Co., Ltd.

Claims (3)

[Claims] 1. The method according to claim 1, wherein 2,6-dichlorobenzoic acid is hydrolyzed in the presence of a copper compound and dimethylamine or a secondary amine selected from amine compounds represented by the following formula (I). A method for producing γ-resorcinic acid. Embedded image (In the formula, Z represents an atomic group necessary for forming a 5- to 8-membered nitrogen-containing heterocyclic ring.) 2. The method for producing γ-resorcinic acid according to claim 1, wherein the secondary amine represented by the formula (I) is morpholine, piperidine, pyrrolidine or piperazine. 3. The γ-resorcinol according to claim 1, wherein the copper compound is at least one selected from cuprous chloride, cupric chloride, cuprous oxide, cupric oxide or cupric sulfate. Method for producing acid.